The present invention pertains to a prostatic stent and processes for the manufacture of such prostatic stent made of a metallic material. More specifically, the invention relates to a prostatic stent for non-surgical treatment of obstruction of the prostatic urethra, such as may arise in connection with benign prostatic hyperplasia or prostatic carcinoma.
A commonly occurring disorder in urology is the obstruction of the prostatic urethra. The disorder occurs in males due to enlargement of the prostatic gland, due either to hyperplasia or to cancer. A condition often found in older males is known as benign prostatic hyperplasia (BPH), and the condition can cause a plurality of inconvenient symptoms, such as difficulties in urination, strongly reduced capacity to urinate, and the condition may at times result in complete retention of urine which may lead to severe renal disorders.
The traditional procedure for treating problems associated with enlargement of the prostate gland has up to now been surgery constituted by cutting away interior sections of the prostate gland or complete surgical removal of the prostate. These are, however, procedures unfavored by many patients and there has been a search for alternative ways of dealing with the problem.
U.S. Pat. No. 5,059,169 is an example of such alternative to surgery. This patent discloses a prostatic stent provided with a conical flange disposed within the neck of the bladder, the opposite end of the stent body extending approximately to the verumontanum. The stent is provided with a textured exterior surface that frictionally engages the urethral walls to prevent migration of the stent into the bladder. Migration in the opposite direction is prevented by the conical flange.
However, this prior art high-friction prostatic stent has associated disadvantages, particularly at and around the conical flange disposed within the neck of the bladder due to the fact that the end of the stent does not conform to the bladder neck and in view of the fact that the proximal end of the stent is designed perpendicular to a center line of the body of the stent. This design means that the stent cannot be placed optimally to cover the complete bladder neck. Either it causes urinary stones (calculi, encrustation) to form on the device protruding into the bladder or the device does not completely cover the circumference of the bladder neck when the stent is placed further down the prostatic urethra. Thus, in using this device one runs the risk of not relieving the obstruction.
One object of the present invention is to provide an improved prostatic stent for the treatment of bladder outlet obstruction caused by an enlarged prostate.
Another object of the present invention is to provide a prostatic stent having a shape conformed to the neck of the urinary bladder to avoid urinary calculi or encrustation or to avoid uncovered areas of the prostatic urethra adjacent to the bladder neck.
Still another object of the invention is to provide a prostatic stent while avoiding migration of the stent into the bladder or distally towards the sphincter.
Yet another object of the invention is to provide processes for the manufacture of metallic braided prostatic stents showing improved performance when used for solving the problem of non-surgical management of bladder outlet obstruction.
Other objects and advantages of the present invention will be understood upon reading of the following disclosure taken together with the drawing and the appended claims.